UIView+AutoLayout.swift

//
//  UIView+AutoLayout.swift
//
//  Created by Simon Ljungberg on 28/12/16.
//  Copyright © 2016 Redhill. All rights reserved.
//

import UIKit

public extension UIView {

    /**
     Disables auto-translation of resizing masks into constraints, preparing the reciever for Auto Layout.

     - Returns: The receiver.
     */
    @discardableResult
    func forAutoLayout() -> Self {
        translatesAutoresizingMaskIntoConstraints = false

        return self
    }

    /**
     Locks the frame of the reciever with the one of the provided view.

     - Parameter view: The view to lock the reciever's frame with.
     - Parameter padding: Optional padding applied to the frame. Positive values means the view is inset from
        the reciever.

     - Returns: The receiver.
     */
    @discardableResult
    func lockFrame(withView view: UIView, withPadding padding: UIEdgeInsets = .zero) -> Self {
        NSLayoutConstraint.activate([
            self.topAnchor.constraint(equalTo: view.topAnchor, constant: padding.top),
            self.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -padding.bottom),
            self.leftAnchor.constraint(equalTo: view.leftAnchor, constant: padding.left),
            self.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -padding.right),
        ])

        return self
    }

    @discardableResult
    func setContent(of scrollView: UIScrollView) -> Self {
        NSLayoutConstraint.activate([
            scrollView.contentLayoutGuide.heightAnchor.constraint(equalTo: self.heightAnchor),
            scrollView.contentLayoutGuide.widthAnchor.constraint(equalTo: self.widthAnchor),
        ])
        return self
    }

    /**
     Locks the center of the reciever with the one of the provided view.

     - Parameter view: The view which center to lock the reciever's center to.
     - Parameter offsetX: An optional value used to offset the reciever's horizontal center from the one of the
        provided view.
     - Parameter offsetX: An optional value used to offset the reciever's veritcal center from the one of the
        provided view.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToCenter(ofView view: UIView, offsetX: CGFloat = 0, offsetY: CGFloat = 0) -> Self {
        NSLayoutConstraint.activate([
            self.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: offsetX),
            self.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: offsetY),
        ])

        return self
    }

    /**
     Lock the top of the reciever to the one of the provied view.

     - Parameter view: The view which top to lock to the receiver's.
     - Parameter padding: An optional padding to apply between the top of `view` and the reciever.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToTop(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        NSLayoutConstraint.activate([
            self.topAnchor.constraint(equalTo: view.topAnchor, constant: padding),
        ])

        return self
    }

    /**
     Lock the bottom of the reciever to the one of the provied view.

     - Parameter view: The view which bottom to lock to the receiver's.
     - Parameter padding: An optional padding to apply between the bottom of `view` and the reciever.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToBottom(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        NSLayoutConstraint.activate([
            self.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -padding),
        ])

        return self
    }

    @discardableResult
    func lockToLeft(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.leftAnchor.constraint(equalTo: view.leftAnchor, constant: padding).isActive = true
        return self
    }

    @discardableResult
    func lockToLeadingMargin(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: padding).isActive = true
        return self
    }

    @discardableResult
    func lockToTrailingMargin(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -padding).isActive = true
        return self
    }

    @discardableResult
    func lockToRight(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -padding).isActive = true
        return self
    }

    @discardableResult
    func hugRight(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.leftAnchor.constraint(equalTo: view.rightAnchor, constant: padding).isActive = true
        return self
    }

    @discardableResult
    func hugLeft(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.rightAnchor.constraint(equalTo: view.leftAnchor, constant: padding).isActive = true
        return self
    }

    @discardableResult
    func hugBottom(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.topAnchor.constraint(equalTo: view.bottomAnchor, constant: padding).isActive = true
        return self
    }

    @discardableResult
    func hugTop(ofView view: UIView, withPadding padding: CGFloat = 0) -> Self {
        self.bottomAnchor.constraint(equalTo: view.topAnchor, constant: -padding).isActive = true
        return self
    }

    @discardableResult
    func set(aspectRatio: CGFloat, toWidthOfView view: UIView) -> Self {
        self.heightAnchor.constraint(equalTo: view.widthAnchor, multiplier: aspectRatio).isActive = true
        return self
    }

    /**
     Lock the horizontal center of the receiver to the one of the provied view.

     - Parameter view: The view which horizontal center to lock to the receiver's.
     - Parameter padding: An optional offset to apply.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToCenterX(ofView view: UIView, offset: CGFloat = 0) -> Self {
        NSLayoutConstraint.activate([
            self.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: offset),
        ])

        return self
    }

    /**
     Lock the vertical center of the receiver to the one of the provied view.

     - Parameter view: The view which horizontal center to lock to the receiver's.
     - Parameter padding: An optional offset to apply.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToCenterY(ofView view: UIView, offset: CGFloat = 0) -> Self {
        NSLayoutConstraint.activate([
            self.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: offset),
        ])
        return self
    }

    /**
     Lock the width of the receiver with the one of the provided view.

     - Parameter view: The view which width to lock the receiver's to.
     - Parameter multiplier: An optional multiplier applied to the `view`'s width creating the receiver's width.
     - Parameter constant: A constant width modifier.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToWidth(ofView view: UIView, withMultiplier multiplier: CGFloat = 1, constant: CGFloat = 0) -> Self {
        self.widthAnchor.constraint(
            equalTo: view.widthAnchor,
            multiplier: multiplier,
            constant: constant
        ).isActive = true
        return self
    }

    /**
     Lock the height of the receiver with the one of the provided view.

     - Parameter view: The view which height to lock the receiver's to.
     - Parameter multiplier: An optional multiplier applied to the `view`'s height creating the receiver's width.
     - Parameter constant: A constant value to apply to the height.

     - Returns: The receiver.
     */
    @discardableResult
    func lockToHeight(ofView view: UIView, withMultiplier multiplier: CGFloat = 1, constant: CGFloat = 0) -> Self {
        self.heightAnchor.constraint(equalTo: view.heightAnchor,
                                     multiplier: multiplier,
                                     constant: constant).isActive = true
        return self
    }

    @discardableResult
    func setHeight(
        to constant: CGFloat,
        withPriority priority: UILayoutPriority = UILayoutPriority.defaultHigh
    ) -> Self {
        let constraint = self.heightAnchor.constraint(equalToConstant: constant)
        constraint.priority = priority
        NSLayoutConstraint.activate([constraint])

        return self
    }

    @discardableResult
    func setWidth(
        to constant: CGFloat,
        withPriority priority: UILayoutPriority = UILayoutPriority.defaultHigh
    ) -> Self {
        let constraint = self.widthAnchor.constraint(equalToConstant: constant)
        constraint.priority = priority
        NSLayoutConstraint.activate([constraint])

        return self
    }

    @discardableResult
    func makeSquare(fromHeight: Bool = true) -> Self {
        let decidingAnchor = fromHeight ? heightAnchor : widthAnchor
        let dependentAnchor = fromHeight ? widthAnchor : heightAnchor
        decidingAnchor.constraint(equalTo: dependentAnchor).isActive = true
        return self
    }

    @discardableResult
    func lockBaseline(with other: UIView) -> Self {
        self.firstBaselineAnchor.constraint(equalTo: other.firstBaselineAnchor).isActive = true
        return self
    }

    /**
     Add the provided view as a subview of the receiver.

     - Parameter view: The view to add as a subview.

     - Returns: The newly added subview.
     */
    @discardableResult
    func add<T>(view: T) -> T where T: UIView {
        self.addSubview(view)
        return view
    }

    @discardableResult
    func setHugging(priority: UILayoutPriority, for axis: UILayoutConstraintAxis) -> Self {
        self.setContentHuggingPriority(priority, for: axis)
        return self
    }

    @discardableResult
    func setCompressionResistance(priority: UILayoutPriority, for axis: UILayoutConstraintAxis) -> Self {
        self.setContentCompressionResistancePriority(priority, for: axis)
        return self
    }

}